First of all, there always will be some element of 'risk' when coming out to your friends of family, but please don't do it if you aren't sure you will be completely safe! And you don't have to come out to everyone at once or even call yourself aroace (think of saying "I don't want to date or have sex", just describe your feelings).
Back to the topic at hand, I completely understand your feelings. It had taken me several months of thinking and pondering before I could come out as non-binary to my friendgroup, there is a sense of responsibility that comes with telling someone your orientation of gender identity, I was afraid people would judge me, that I would have to prove that my feelings are real not just to myself, but to other people.
It's best to start by taking small steps. As I said, you could come out to only a couple of friends, and when you do, always think of the positive reaction you got from others. Be ready for the worst, but hope for the best. And if you aren't ready for that yet, there are other ways to express yourself: wear green or purple colors, use other symbols associated with asexuality or aromanticism, maybe casually talk about it with your friend or tell them jokes. It may seem silly, but it helps you build your confidence.